Projection display systems employing spatial light modulators, as well as many other image-reproducing systems, prefer only image-data encoded light to be projected on the viewing screens so as to obtain the desired images or videos of pleasant display quality. Non-image data encoded light, such as ambient light and light scattered from the members of the micromirror array devices can degrade the display quality if projected also on the viewing screen and superpositioned with the image-data encoded light. In particular, such superposition may significantly decrease the contrast ratio of the displayed image.
Contrast ratio is the ratio of luminance between the brightest white that can be produced and the darkest black that can be produced. If a display image has a higher contrast ratio, a viewer will judge it to be sharper than a displayed image with a lower contrast ratio, even if the lower contrast image has substantially more measurable resolution.
Therefore, a method and apparatus for avoiding reduction of the contrast ratio due to unexpected light scattering from the functional members of the micromirror array devices are desired.